50/30 pressure switch

[jessl]

We just replaced our 50/30 pressure switch for our water system. And it still keeps going on and off. Pressure only building to 39, shouldn't be at 50?. Also, lost power for about 8 hours before we turned new switch on. No water in the lines. It has stopped clicking on and off, pressure at around 30? Is this correct?

 

[Reach4]

No water in the lines, and what pressure is around 30? I am not sure what you are saying there.

Are you saying the pump keeps going on and off? Sound like your pressure tank could be shot.

Did you check the precharge pressure on the pressure tank with the pump off and the water pressure down to zero? That is done with a tire pressure gauge. It should read 28, and water should not come out of the valve when you measure the pressure. What did that measure?

 

[Sponsor]

 

[jim dandy]

Not a plumber but just my two cents......

Based on what you say, I say the switch is not adjusted correctly. 1st the cut out is set to low, it needs to be set to your desired cut out pressure say 50 psi. 2nd the differential in your case is 20 psi this is also adjustable. Set the cut out and cut in pressure to your desired pressure psi then check the differential to make sure it is what it needs to be, 15 to 20 psi sounds ok. On a well I think I would set the cut out a little higher say 55 lbs.

 

[Valveman]

Probably too much air pressure in the tank. With a 30/50 switch you should have no more than 28 PSI air in the tank.

 

[NHmaster3015]

First of all if the pressure switch is a 30/50 and its shutting off at 30 then most likely the gauge is bad followed by the new pressure switch is either not properly adjusted or bad but....I'd bet on the gauge 1st.

When you replaced the pressure switch did you clean out the line/connection(s) going to it? They fill up with crap and then the pressure switch can't feel the pressure changes.

If its a 30/50 switch, the pressure in your tank should be at 28 lbs with the pump not running and the pressure bled off the water system.

With the pump off and the pressure bled off there should be no water in your pressure tank and especiall no water should come out when you open the shraeder valve on the tank.

I assume the pump is a submersible but if its a jet pump it may not be developing enough pressure. Usually due to a plugged venturi but impeller wear, a scution leak or a static that has dropped below the pumps performance curve.

If its a submersible the impellers could be badly worn, the motor could be defective, the well may be running dry.

So many things it could be but start with the gauge and the pressure tank.

 

[jim dandy]

error..........sorry

 

[LLigetfa]

We just replaced our 50/30 pressure switch for our water system. And it still keeps going on and off. Pressure only building to 39, shouldn't be at 50?

If the pressure only builds to 39, what is causing the pump to go on and off? Are you watching to see if the contacts open and close? If they are, the tank may be waterlogged or the switch is too far away from the tank.

If the contacts stay closed, suspect that the pump is going into thermal overload.

If the pump runs continuously and won't build enough pressure, suspect a hole in the pipe if the pump is a sub, or a plugged jet if it is a jet.

 

[LLigetfa]

Not a plumber so if I am wrong I have a reason, but I disagree with you on this.

An expansion tank normally comes from the factory with a precharge of around 40 lbs psi. depending on manufacturer. It is up to the end user to adjust the pressure within the expansion tank to suit their particular application. In This case the well pump relay being used is 30/50 but even at that it's iffy and needs to be checked with an accurate pressure gage.. That being the case the expansion tank should be pressurized with 52 lbs psi of air..

You are giving bad advice. The precharge on the bladder needs to be 2 - 5 PSI less than the kick-in setting of the switch, so 25 - 28 PSI.

 

[NHmaster3015]

Not a plumber so if I am wrong I have a reason, but I disagree with you on this.

An expansion tank normally comes from the factory with a precharge of around 40 lbs psi. depending on manufacturer. It is up to the end user to adjust the pressure within the expansion tank to suit their particular application. In This case the well pump relay being used is 30/50 but even at that it's iffy and needs to be checked with an accurate pressure gage.. That being the case the expansion tank should be pressurized with 52 lbs psi of air.

Expansion tanks come in many sizes from small to use on water heaters and boilers and larger size in many gallons to use on main line well systems.

Expansion tanks should be pressurized with air between 1 & 2 lbs psi above the maximum water pressure reached through out the day on the system it is being used on, otherwise the tank will fill with water and be absolutely useless. Just my non plumber experience opinion, sorry if I got this subject wrong.

Ahhhhh.....NO! The pressure tank gets pressurized to 2 lbs below CUT IN pressure or in the case of a 30/50 switch....28lbs

 

[jim dandy]

You have a few things going on here.

Either the cut in cut out relay is defective or some one has been tinkering because it is way off adjustment. Both the cut in and cut out pressure settings are off plus the differential setting is off also. If you allow the well pump to keep cycling on and off for a length of time you risk burning up the well pump motor as the motor uses a lot of current spinning up to speed.

 

[jim dandy]

You are giving bad advice. The precharge on the bladder needs to be 2 - 5 PSI less than the kick-in setting of the switch, so 25 - 28 PSI.

Error in my post..............my apology folks

 

[NHmaster3015]

Jim, you are referencing a system where water is heated as in the hot water side of the supply system. We are talking about the cold water inlet side of the system and in this case the tank pressure needs to be 2 lbs below cut in. As far as a professional point of view, believe me, those of us that have posted are about as professional as professional gets, myself having 40 years of experience. IOW, your research on the subject has been in the wrong area.

The link you posted is for a water heater and has nothing to do with the subject at hand.

 

[LLigetfa]

Elvis has left the building on this.........

Whatever...

You are obviously confusing expansion tanks with well system bladder tanks.

Don't give advice outside your area of expertise.

 

[jim dandy]

Jim, you are referencing a system where water is heated as in the hot water side of the supply system. We are talking about the cold water inlet side of the system and in this case the tank pressure needs to be 2 lbs below cut in. As far as a professional point of view, believe me, those of us that have posted are about as professional as professional gets, myself having 40 years of experience. IOW, your research on the subject has been in the wrong area.

The link you posted is for a water heater and has nothing to do with the subject at hand.

I stand corrected, I thought this was about an expansion tank as used in a hot water heater. You are correct.

 

[DonL]

I stand corrected, I thought this was about an expansion tank as used in a hot water heater. You are correct.

Feel free to use my picture.



It is best to keep a flashlight handy.


Have Fun Everyone.

 

[Valveman]

See how confusing a simple little pump system can be? I am just guessing there is too much air in the tank because they usually come pre-charged at 38 PSI. With a 30/50 pressure switch, this would make the pump bounce on and off quickly. When it finally did stop for a minute, the gauge would probably read about 38 PSI, because that is how much air is in the tank.

When it drops below 30 the pump will start, and the same thing will happen all over again. Letting the air out to 28 PSI or raising the pressure switch setting to 40/60 will probably smooth things out.

 

[NHmaster3015]

See how confusing a simple little pump system can be? I am just guessing there is too much air in the tank because they usually come pre-charged at 38 PSI. With a 30/50 pressure switch, this would make the pump bounce on and off quickly. When it finally did stop for a minute, the gauge would probably read about 38 PSI, because that is how much air is in the tank.

When it drops below 30 the pump will start, and the same thing will happen all over again. Letting the air out to 28 PSI or raising the pressure switch setting to 40/60 will probably smooth things out.

I would have said the same thing except that he didn't change his pressure tank and I assumed (which is always a mistake LOL ) that he replaced his old 30/50 with a new 30/50 so the tank should have been either already set right or the tank is bad. OTOH, this whold thing may very well have been (and still is) the result of a bad pressure tank.

 

[Valveman]

And if an old 30/50 switch had been turned up to 40/60, replacing it with a new 30/50 switch would cause those symptoms. But it could also easily be a bad tank as you said.

 

[DonL]

I will pull a guess out of my ass.

The switch was replaced to fix a problem, that it did not fix.

The tank may be waterlogged and until that is fixed it will not work.


Or a CSV System Would fix it.


Just my two cents.

 

[LLigetfa]

I will pull a guess out of my ass.

The switch was replaced to fix a problem, that it did not fix...

Ja, that would be my guess too, that an underlying problem burned up the old switch and the problem remains.